Kazuki Nishina, a notable Edel Rose alumnus, forms the Prism Star group Over the Rainbow with Koji Mihama and Hiro Hayami. He specializes in academy-style Prism Shows, a structured approach designed specifically to appeal to female audiences. Kazuki mentors newer students, appointing Taiga Kougami as his successor while undertaking training under Rei Kurokawa to refine his own skills. During the Prism King Cup, his performance of "Freedom" restores the damaged stadium and revitalizes the audience's excitement, resulting in his disqualification from the competition.

He maintains a significant rivalry with Schwarz Rose's street-style performer, Alexander Yamato, who views Kazuki as a direct competitor and repeatedly challenges him to duels, embodying the conflict between their performance philosophies. Following the Prism King Cup and Koji Mihama's return from Hollywood, Kazuki reunites with Over the Rainbow, continuing their collaborative work as Prism Stars.